What are ancillary services in power systems?

Active power reserves and reactive supply are the most common ancillary services in power systems. In this chapter we described some relevant issues highlighting important differences in the classification, technical requirements and economics of these services.

How are ancillary services procured?

As illustrated before, ancillary services are procured in the mid or long term through tendering processes or bilateral contracts. Some studies focus on pricing and procuring reserves by the ISO over a mid or long term (weeks, months or years) [33, 34].

How much do ancillary services cost?

Additionally, ancillary services are significant in the system’s budget. For example, in the United States the cost of these services was roughly estimated to be between 5% and 25% of total generation and transmission costs . Here, we separate the ancillary service costs as illustrated in Fig. 1.

What are the different types of ancillary services?

There are two broad categories of ancillary services: Other types of ancillary services provision include: Frequency control refers to the need to ensure that the grid frequency stays within a specific range of the nominal frequency.

How do ancillary services affect economics?

With the unbundling of ancillary services comes the necessity of determining how to pay the providers and charge the users. In this context, it is important to identify some aspects that influence the economics of these services: Ancillary service pricing: determining the price of a specific service.

Are price mark-ups a performance indicator for ancillary services designs?

For policy-making in this context, the present thesis provides a generic evaluation framework for ancillary services designs. The framework entails a novel approach to use price mark-ups as a performance indicator for ancillary service interactions and design efficiency.